台灣是個海島國家，水資源是最重要的永續資源，為了培育國內環境教育師資，由教育部主辦，計畫經費由教育部、環保署、經濟部水利署共同補助「水環境教育師資研習暨資源網站建置整體計畫」，本計畫為三年計畫，總共製作五個線上學習課程模組，課程內容不僅涵蓋科學、生態學與工程等知識，也將社會、政治與經濟議題等影響毀環境發展與保護的相關議題納入。舉辦七次線上研習課程，總共有12,288位學員報名參加。本計畫完成了針對水環境教育國內規模最大、人數最多的線上師資研習計畫。本文除針對計畫執行之概況做一介紹之外，並且介紹透過全面性學員問卷調查所呈現之國中小學教師線上研習之特性分析以及成效評估，以作為未來各單位推動大規模線上課程之參考。

Being an island nation, the most important element of sustainability is the water environment. It is vital to quicken the pace of teachers on the job training in order for them to educate students the importance of water environment and the ways that they can help to protect it. Consequently, the Ministry of Education, the Environmental Protection Agency, and the Water Resources Agency co-sponsored a 3-year eLearning project to transfer the core knowledge on water environment to the school teachers in this water education capacity building program. In total, this program produces five eLearning content modules and 80-hour asynchronous courses. The course topics not only covers science, ecology, engineering knowledge on water environment but also include social, political, and economical issues encompassing water resources development and water environment protection. Based on these courses, seven eLearning programs were delivered and attracted more than 12,288 participants. As far as we know, this is the most extensive eLearning program dedicated for teachers on water environment education in Taiwan. This paper presents an overview of project and discusses important aspects and effectiveness of the very large-scale eLearning program based on the analysis of questionnaires to all the participants. The results serve as the most valuable firsthand knowledge on eLearning program participants on which the planning of all future large-scale eLearning programs should taken into account.